Control means for multiple hydraulic jacks



March 7, 1950 R. o. BILL CONTROL MEANS FOR MULTIPLE HYDRAULIC JACKS Filed Jan. l0, 1949 emes un. v. 195o coN'raoL MEANS Foa MULTIPLE HYDRAULIC .mons

neben o. sin, san Leandro, cem. Application January l0, 1949, Serial No. 70,132

Claims. (Cl. 60-97) l This invention relates to improvements in control means for hydraulic jacks, and particularly to hydraulic jacks used for elevating and lowering vehicle bodies, and provides positive means for elevating and lowering the various points on a vehicle body uniformly irrespective of the variations in load at the various points., and is particularly applicable tothe truck, trailer, and semitrailer elevating and lowering means disclosed in `my copending applications Serial 'Numbers' 34,963, led June 24; 1948; 63,694, led Dec. 6,

1948; 27,394 (now Patent`N0. 2,475,443 issued July 5, 1949), and 27,395, iiled May I7, 1948; all of which disclose hydraulic means for elevating and lowering the beds or'bodies of trucks, trailers, and semi-trailers; though the invention is Y `not limited to this particular use, being applicable to any ease where a plurality of jacks are to be simultaneously operated. j

The invention also includes auxiliary means for varying the degree of rise or drop at the various the various jacks may be points aboutthe vehicle so that the vehicle body 1 or bed can be tilted in any desired manner, diagonally, longitudinally, or transversely. With this auxiliary means any one of the jacks can beindividually operated, or any two or more simultaneously and equally operated, making control of the battery of Jacks universal.

A As is well known, when a plurality of jaclzs is simultaneously operated, the Back with the'least load will advance ahead of the heavier loaded ones. and with fairly great variations in loads the one with the vleast load is liable to operate alone if the fluid is supplied from a single source.

l With my invention all jacks will operate equally irrespective of the variations inthe -loadson the various jacks, and ii variations in the degree oi operations of the various jacks 'is desired, the auxiliary means will permit of such variations irrespective of the variations in loads, while also permitting replenishment of any iiuid which may have leaked from any jack, and also permit hand operation of the jacks either simultaneously or individually in case of failure of the main source of iiuid under pressure. Y l

The objects and advantages-of the invention are as follows. 4

ll'irst, to provide a system for operation ofa. plurality oi hydraulic jacks in which all Jacks in the system will operate to'the same degree irrespecti've ot variations inthe loads on the respective jacks.

econdtoprovide a system as outlined in which operation of the jacks is carried out on the basis system whereby all Jacks will be advanced or retracted to the same degree irrespective of any variations in loads on the Jacks.

Third, to provide a system as outlined in which individually controlled and operated at will. e 5

Fourth, to provide a system as outlined in which means is provided for individually replenishing the fluid supply in any jack at will.

Fifth, to provide a system as outlined with power operable means for operating the jacks, and with auxiliary manually` operable means for operating the jacks in the event of failure of the power operable means.V

In describing the invention reference will be had to the accompanying drawing, in which:

liig,v 1 is a schematic drawing of the entire system. A

Fig. 2 is a section taken on line'2-2 of Fig. l. Fig. 3 is an enlarged verticalsection through the manually-operable pump control for individual operation of thejacks and for replenishment of iluidin the individual jacks as occasion may require. p

The invention is particularly applicable to vehicles and hydraulic elevating and lowering means for the beds or bodies thereof as disclosed'in vthe aforementioned patent applications, in which a trailer, semi-trailer, or tractive front end of `a truck I 0 has a hydraulic jack I I having a cylinder I2 and a piston rod I3 which is coupled to the front end I4 of the trailer, semi-trailer, or truck body or bed I5, though not limited to a singlev jack for this end; and one or more jacks I6 and I1 for the respective rear'wheels of the vehicle which are mounted von axles I8 and I9 fixed in hubs 20 and 2| which are integral with the pistons 22 and y l pump 29 for delivering this fluid under pressure all for cach individual Jack in the and which may be driven by any suitable means such as by the vehicle engine or by a motor 30; thev pump being preferably of a reversible type with the driving means also reversible, a master cylinder -having a piston 32 and piston rod 33 on the outer end of which is attached a plurality of piston rods 35, 36 and 31 equal in number to the number of hydraulic jacks to be operated, and

each piston @rod having a piston 38, 39, 40, with the pistons operating in their respective cylinders 4I, 42 and 4,3, and the cylinders mounted in common mounting means such as the brackets 44 and BAOQMB 4l and which are mounted `on some portion of the .vehicle such asthe drive end of the truck, front end-of the trailer, or on the soose neck 49 of the A semi-trailer.

The respective'trans'froyimders 41, 42 and n have displacements equal' to the displacements of the hydraulic jacks I I, lII and I1 and are respectively connected to the working ends of the cylinders.

A'n auxiliary jack pump 41 is provided for manual operation of the jacks in thev event of.

failure of the power for driving the pump 2l. and when limitedto that purpose may be a conventional multiple pump unit as is conventionally used for jacks; however, a pump is preferred which canbe used for manual operation of the jacks, as also for replenishingthe fluid supply in' the jacks, and for individual control of the various Jacks, and the control mechanism is illustrated in one concept in Fig. 3, in which the cylinder 48 has an intake valve 49, and a discharge pas# rest on this Vlow side, freeing the valves, so that' duid is taken from the tank 28 through the line 89 thence through the several intake ports 8|, drawn past the valves 49, when the pump pistons are'drawn upward, and discharging through the 'passages '50- past the valves 5I to the respective conduits l5, 96 51, this being normal operation.

`rn oase one of the jacks should leak part of its oil,-say` the jack Il, the knobs 14 and 1S. are adiusted'to move their associated cams tothe position shown in Fig. 3,'0r mid-position, while.

the knob 1s is 'left in its normal position with sage 50 closed normally by a valve 5I against return of fluid to the supply.

Rotatabie in the lower end of the base -52 is a shaft 53 on which is mounted a cam 54 having a low side 55 and a high side 56. Plungers 51 and 58 operate slidably through the housing with one end of eachv cooperating with the cam and the other ends cooperating with or cooperatively related to the respective valves, the other end of the plunger slightly clearing the valve when retracted as indicated at 59, and springs 60 urge the plungers t cooperate with the cam and retract from the valves; the pump intake being indicated at 6l and the discharge at 62.

For normal operation the discharge ends of the both valves operating. In this case, the' two pumps 'I8 and 19 will merely idle, drawing oil from the supply tank 28 and then returning it, while the other pump v11 will pump oil to the jack il.

When the bed is to be lowered, it is merely necessary to turn the knobs to their farthest clockwise position, in which case both plungers 51 and 58 will rest -on the high side56 of the respective cams, keeping both valves open. Thus it is posv sible with this arrangementto selectively supply transfer cylinders 4I, 42 andv are filled with oil, the pistons being fully retracted, and a supply of oil is provided'in the tank 28. The bed or body the head 34, the pistons 38, 39 and 40 are driven forward, forcing the oil 64 in these cylinders through the respective conduits 65, 66 and 81 to the respective jacks I1, I6 and II, elevating the bed I equally at all points of suspension by the jacks, and to a height proportionate to the degree of operation of the pump 29 being terminated when the desired elevation of the bed is attained. v When the bed is to be lowered, the pump 29 can be reversed, or the valve 68 may be opened to allow the oil in the head end 63 of the cylinder to drain back to the supply'tank under the urgence of the load on the jacks. When the bed has reached the desired level, the valve is closed, holding the bed at that level. L

In the event of power failure so that the pump 29 cannot be operated, the pump 41 is manually operated, delivering fluid from the supply 28 through the pipe 69, thence through the pump 41, and lines 10, 'Il and 12 to the conduits 65, 68

and 61 and thence to the jacks, the transfer cylinders being filled with oil and the pistons retracted so that only the' jacks need be lled to cause the raising of the bed. This pump is operated by the handle -13 and controlled by the knobs 14, and 16, the pump shown being the conventional 3-cylinder hydraulic jack Dump.

With the arrangement shown in Fig. 3,- comadditional oil to the respective jacks, selectively drain fromany or all lacks, Pump to selected jacks while draining from others, or pump equally to all jacks foremergency operation in the event of power failure, making operation selective or universal atwill. Y

I claim:

1. Operating means for a plurality of hydraulic jacks comprising a master cylinder'and a supply of fluidunder pressure therefor and control means for said supply; transfer cylindersequal in number to the numberof jacks toY be operated and having displacements equalto that of the jacks operated thereby, and asupply of fluid for each cylinder and equal to its displacement, communication between each cylinder and its jack; a master piston for said master cylinder and a transfer piston for each transfer cylinder and operative connections between said master piston and said transfer cylinders for equal operation oi' the transfer pistons by the master piston; a plurality of pumps equal in number to the number of hydraulic jacks, and manual operating means for simultaneously and equally operating all of said plurality of pum'pspwith the respective pumps having communication between said supply of fluid and the respective jacks, and said plurality of pumps each including control means individually operable for controlling idling in, drainage from, and delivery of fluid to, the respective jacks at will whie all of said plurality of pumps are simultaneously operated.

2. Means for simultaneously operating a plurality of hydraulic jacks to the same degree irrespective of variations in loads on the jacks, comprising; a transferl cylinder for each jack and having a communicating connection therewith and having a supply of liquid equal to the displacement of the jack plus the internal volume of the connection; a piston for each transfer cylinder with the strokes of all pistons being equal; and' means for simultaneously voperating all of the pistons simultaneously and to the same degree; whereby operation of the said pistons in opposite directions will simultaneously operate all jacks in equal degrees of movement in respective directions; a pump for each jack and having a communicating connection therewith; means for plete control of the several jacks. `collectively-or manuallyoperating all of said-pumps simultane- Normally, the knobs 1l.

ously and to the same degree; each oi' said pumps including valve control means adjustable to three positions, in one of which the pump idles, in another of which liquid will drain through the pump from the jack. and in the other of which the pump deliversI liquid under pressure to the jack, and a supply of liquid for said pumps.

3. Means for simultaneously operating a piurality of hydraulic jacks to the same degree irrespective of variations in loads on the jacks, comprising; a transfer cylinder for each jack and having a communicating connection therewith and having a supply of liquid equal to the displacement of the jack plus the internal volume of the connectionya piston for each transfer cylinder with the strokes of all pistons being equal: and means for simultaneously operating all of the pistons simultaneously and to the same degree; whereby operation of the said pistons in opposite directions will simultaneously operate all jacks inequal degrees of movement in i respective directions; a pump for each jack and having al communicating connection therewith;

kmeans for manually operating all oi.' said pumps simultaneously and to the same degree; each of said pumps including valve control means adjustable to three positions, in one of which the pump idles, in another of which liquid will drain through the pump from the jack, and in the other of which the pump delivers liquid under pressure to the jack, and a supply of liquid for said pumps; said means for simultaneously operating all of said transfer-cylinders comprising; a master cylinder having a piston terminating in a head; a piston for each transfer cylinder and xed to said head; a supply of uid for said master cylinder, and a reversible pump for delivering liquid to and for withdrawing liquid from said master cylinder, and means for operating said reversible pump.

4. Means for simultaneously operating a plurality of hydraulic jacks to the same degree irrespective of variations in loads on the jacks, comprising; a transfer cylinder for each jack and having a communicating connection therewith `and having a supply of liquid equal to the displacement oi the jack plus the internal volume of the connection; a piston for each transfer cylinder with the strokes of all pistons being equal; and means for simultaneously loperating all of the pistons simultaneously and to the same degree; whereby operation of the said pistons in opposite directions will simultaneously operate all jacks in equall degrees of movement in respective directions; a plurality of control pumps equal in number to the number of hydraulic*v jacks and means for simultaneously operating said control pumps to an equal degree, and a supply of liquid for said control pumps; a valvesystem for each pump and control means'therefor manually adjustable at will\to one which liquid is delivered toits jack, in another of which the pump idles while retaining the contained liquid in its jack. and in the other of which the liquid in the jack is released for pas,

position in sage through the pump to said supply, irrespective of the adjustments of the other control pumps, whereby the control -pumps may be used for simultaneously or individually operating the jacks in either direction, at will, irrespective of operation of said means for simultaneously opcrating all of the pistons.

5. Means for simultaneously operating a plurality of hydraulic jacks to the same degree irrespective of variations in loads on the jacks, comprising; a transfer cylinder for each jack and having a rcommunicating connection therewith and having a supply of liquid equal to the displacement of the jack plus the internal volume of the connection; a piston for each transfer cylinder with the strokes of all pistons being equal; and means for simultaneously operating all of the pistons simultaneously and to the same degree; whereby operation of the said pistons in opposite directions will simultaneously operate all jacks in equal degrees of movement in re spective directions; said means for simultaneously operating all of said transfer cylinders comprising; a master cylinder having a piston terminating in a head; a piston for each transfer cylinder and xed to said head; a supply of fluid for said master cylinder, and a reversible pump for delivering liquid to and for withdrawing liquid from said master cylinder, and means for operating said reversible pump; a plurality of control pumps equal in number .to the number of 'hydraulic jacks and means for simultaneously operating said control pumps to an equal degree, and a supply oi liquid for said control pumps; a

valve system for each pump and control meanstherefor manually adjustable at will to one position in which liquid is delivered to its jack, in another of which the pump idles while retaining the contained liquid in its jack, and in the other of which the liquid in the jack is released for passage through the pump to said supply, irrespective of the adjustments of the other control pumps, whereby the control pumps may be used for simultaneously or individually operating the jacks in either direction, at will, irrespective of operation of said means for simultaneously operating all of the pistons.

' ROBERT O. BILL.

REFERENCES lCITED The following references are of record in the flle of this patentz' UNITED sTATEs PATENTS 

